臺灣博碩士論文加值系統

電阻式記憶體(Resistive Random Access Memory, ReRAM)為金屬─絕緣─金屬之簡單三明治結構(sandwich structure)，透過在上下電極施加偏壓改變電阻值來儲存資料。本研究利用過渡金屬二硫化物(transition metal dichalcogenides,TMDs)作為絕緣層材料，此二維材料在近期因超薄的材料厚度與特殊的電子特性吸引研究人員的興趣，與常見的石墨烯相比，它具有的帶隙為本徵半導體(intrinsic semiconductor)，並可藉由改變電場來控制其能隙大小，因此有許多應用於場效電晶體的研究，而大多數過渡金屬二硫化物皆有H(Hexagonal)及T(Trigonal)兩種晶型，分別呈現半導體和金屬性質，因此在電阻式記憶體的研究中也有討論兩種晶型的轉換。
本研究利用濕式轉印法將生長於藍寶石基板上之二硫化鉬、二硫化鎢轉印至矽基板上，以不同清潔基板方式使二維材料轉印後能有最潔淨的表面，並探討完成轉印後浸泡不同溶液、溶液溫度對移除二硫化鉬、二硫化鎢表面殘留PMMA之影響。透過加熱退火移除二維材料與基板之間的水氣與表面殘留PMMA使其更服貼於基板表面。最後藉由AFM、PFM、C-AFM、Raman、PL等材析方法鑑定二硫化鉬/二硫化鎢凡得瓦異質結構，再利用電性量測系統量測ReRAM元件之電流-電壓曲線(I-V curve)，除探討二硫化鉬/二硫化鎢凡得瓦異質結構應用於ReRAM電性量測影響，亦探討單層二硫化鉬、單層二硫化鎢之電性影響。
實驗結果顯示，退火 200℃ 可使表面PMMA殘留物大幅去除，濕式轉印後的二硫化鉬/二硫化鎢結構並未被破壞，使用拉曼、PL光學量測，轉印前後峰值不變，且此兩種材料的凡得瓦異質結構有鐵電效應。

Resistive Random Access Memory (ReRAM) is a simple sandwich structure (sandwich structure). This study uses transition metal dichalcogenides, TMDCs as insulating layer materials.
Many studies show that there are H (hexagonal) and T (trigonal) represent semiconductor and metal properties respectively. In this study, we use wet transfer to transfer molybdenum sulfide（MoS2） and tungsten sulfide （WS2）grown on the sapphire substrate to the silicon substrate. Different cleaning methods were used to make 2D materials more clean after transfer. Finally, we use AFM, PFM, C-AFM, Raman, PL and other material analysis instrument to identify the MoS2, WS2 van der Waals heterostructure, and then use the probe station to measure the I-V curve of the ReRAM device. Therefore, we measurement , I-V curve of the single-layer MoS2 , WS2 based memristor device.
The experimental results show that annealing 200°C will remove most of the PMMA photoresist of the substrate and material surface. MoS2 ,WS2 2D material’s structure will not destroyed after wet transfer. Using Raman and PL optical measurements, the peak value remains unchanged after transfer. Ferroelectric effect have been found on MoS2 ,WS2 van der Waals heterostructure.

摘要 i
ABSTRACT ii
目錄 iii
圖表目錄 vii
第一章 緒論 1
1.1 前言 1
1.2 揮發性記憶體 (Volatile Memory) 2
1.2.1 動態隨機存取記憶體 (Dynamic Random Access Memory, DRAM) [1] 2
1.2.2 靜態隨機存取記憶體(Static Random Access Memory, SRAM) [2] 2
1.3 非揮發式記憶體(Non-volatile Memory) 3
1.3.1 電阻式記憶體 (Resistive Random Access Memory, ReRAM) 3
1.3.2 鐵電式記憶體 9
1.4 二維過渡金屬硫化合物（TMDs） 13
1.4.1 結構特性 13
1.4.2 能帶結構與電性 13
1.4.3 二硫化鉬（Molybdenum disulfide, MoS2） 14
1.4.4 二硫化鎢（Tungsten disulfide, WS2） 15
1.5 研究動機與文獻回顧 15
第二章 儀器介紹與工作原理 17
2.1 旋轉塗佈儀 (Spin coater) 17
2.2 熱蒸鍍系統 (Thermal Evaporation) 17
2.3 轉印平台 (Transfer platform) 19
2.4 掃描式電子顯微鏡 (Scanning Electron Microscope, SEM) 19
2.4.1 電子槍 (electron gun) 20
2.4.2 掃描式電子顯微鏡偵測之訊號 22
2.5 X光能量散佈分析儀 (Energy Dispersive X-ray Spectrometer, EDS) 25
2.5.1 儀器介紹 25
2.5.2 工作原理及其架構 25
2.6 X光粉末繞射儀 (X-ray Powder Diffraction, XRD) 26
2.7 X光電子能譜儀(X-ray Photoelectron Spectroscopy, XPS) 27
2.7.1 儀器原理 27
2.7.2 儀器架構 28
2.8 拉曼光譜儀(Raman spectroscopy) 28
2.8.1 儀器原理 28
2.8.2 儀器架構 30
2.9 光致激發螢光光譜儀(Photoluminescence, PL) 31
2.10 電子束微影系統(Electron Beam Lithography System) 32
2.11 原子力顯微鏡（Atomic force Microscope, AFM） 33
2.11.1 儀器原理 33
2.11.2 儀器架構 35
2.11.3 壓電力原子顯微鏡 (PiezoresponseForce Microscopy, PFM) 36
2.11.4 導電原子力顯微鏡 (conductive atomic force microscope, C-AFM) 38
2.12 電性量測系統(Probe station) 39
第三章 實驗試劑、方法與元件製備 40
3.1 實驗試劑 40
3.2 實驗方法與元件製備 40
3.2.1 基板清洗流程 40
3.2.2 溼式轉印流程 41
3.2.3 乾式轉印流程 43
3.2.4 製成圖形電極基板(pattern) 43
3.2.5 TEM 樣品製備 45
第四章 實驗結果與討論 46
4.1 表面形貌分析 46
4.1.1 不同溶液清潔表面形貌分析 46
4.1.2 不同丙酮浸泡時間表面形貌分析 48
4.1.3 有無退火表面形貌分析 49
4.2 TEM表面形貌分析與選區繞射 51
4.3 機械剝離法MoS2、WS2晶體XRD結構繞射分析 53
4.4 XPS 元素鍵結分析 54
4.4.1 單層MoS2 之XPS 元素鍵結分析 54
4.4.2 單層WS2 之XPS 元素鍵結分析 56
4.5 機械剝離法MoS2、WS2晶體SEM EDS元素分析 57
4.6 PL螢光分析 59
4.6.1 MoS2 PL螢光分析 59
4.6.2 WS2 PL螢光分析 61
4.6.3 MoS2、WS2 異質結構PL螢光分析 [23] 62
4.7 Raman晶格與分子振盪、轉動分析 64
4.7.1 MoS2 Raman分析 64
4.7.2 WS2 Raman分析 65
4.7.3 MoS2、WS2 異質結構Raman分析 67
4.8 PFM壓電響應及電鐵電特性量測 69
4.8.1 單層MoS2之PFM圖 70
4.8.2 單層WS2之PFM圖 71
4.8.3 凡得瓦異質結構MoS2和WS2之PFM圖 73
4.8.4 多層MoS2和WS2之PFM圖 74
4.8.5 不同基板的鐵電效應 75
4.8.6 單層MoS2和WS2之鐵電特性 76
4.8.7 凡得瓦異質結構MoS2和WS2之鐵電特性 77
4.8.8 多層MoS2和WS2之鐵電特性 78
4.9 C-AFM電性量測 79
4.10 SCM量測 84
4.11 I-V電性量測 85
第五章 結論 88
參考文獻 89

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